"The area of study was restricted to those common flowering herbs of Denton County, Texas, which have conspicuous flowers or a conspicuous flower cluster. There were, however, many plants included in this flora which are common to several counties of north-central Texas. Since there has been no previous key devised for the herbs of Denton County, Texas, the purpose of this key was to provide a flora which could be used by elementary and high school instructors, as well as any other interested persons who lack an extensive knowledge of botanical nomenclature." -- leaf iv.

Examensarbete.

Please read the abstract in the section 00front of this document / Dissertation (MSc (Soil Science))--University of Pretoria, 2006. / Plant Production and Soil Science / unrestricted

From the Proceedings of the 1971 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 22-23, 1971, Tempe, Arizona / The rotadisk rainulator is a recently developed rainfall simulator utilizing a full-cone-spray type nozzle. Its unique feature is the rotation of disks of various size openings that makes it possible to produce intensities from close to zero up to full nozzle capacity. Disks may be quickly changed, making it possible to study the effects of various intensities on infiltration rates, such as occur in natural storms. For all intensities above 1.0 in/hr, the instrument comes closer to duplicating kinetic energies and momenta of natural rainfall than any other type of rainfall simulator. Little rainfall-runoff data are available on most of the Lower Gila watersheds. Infiltration rates were therefore determined using the rotadisk rainulator on recompacted soil samples from the watershed. The results permitted a ranking of the watersheds on the basis of infiltration rates, which supports an independent flood frequency analysis indicating that the flood threat from subwatersheds along the Gila is much lower than had previously been projected. When the instrument is taken into the field, it should be possible to directly determine the infiltration rates of different soil and vegetation types, which will be of more use to hydrologists than data from recompacted samples

From the Proceedings of the 1975 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 11-12, 1975, Tempe, Arizona / Evaporation of water from bare soils is an important consideration in the scheduling of many farming operations in both irrigated and dryland agriculture. Accurate predictions of bare soil evaporation can serve as the basis for decisions to increase the acreage planted with a given crop. An alternative is presented to previous approaches to bare soil evaporation estimation by empirically correlating the ratio of daily totals of actual to potential evaporation and the amplitude of the diurnal surface soil temperature wave. Since evaporation is directly related to the surface soil water pressure, the soil thermal inertia technique might be capable of prescribing relative bare soil evaporation rates which, combined with potential evaporation calculations, could allow determination of actual evaporation rates over the entire range of soil drying.

Cultural heritages are environments created by humans that are considered to have a conservation value for the posterity. They can be seen as one of society's non renewable resources. It is important to have knowledge of how cultural heritages are affected by future climate changes. The water flow in Uppsala is estimated to increase during winter and decrease during spring and summer. Precipitation will gradually increase as well as the intense short period precipitation. The average temperature is estimated to increase as well. Despite the increased precipitation the soil moisture is predicted to decrease, as a result of the rising temperatures with an increased evaporation rate as a consequence. This study is carried out for the county administrative board in Uppsala county, in the field of climate change adaptation on the unit for emergency preparedness and civil contingency.The study focuses on three areas in Uppsala, city centre, Hågadalen and Vallsgärde. Focus in the study is on the earth scientific consequences related to flooding as well as changes in precipitation. Maps has been produced in ArcGIS where floodings, soil types and cultural heritages are presented (appendix 1-3). 17 cultural heritages within the three areas has been established to be affected from floodings from Fyrisån where most of them are situated in the city centre of Uppsala. The changes in precipitation are the same throughout all studied areas, to what degree it will impact the cultural heritages depends on the characteristics of them. The ground is estimated not to be strongly affected by the increased amounts of water. But smaller settlings and land slides in clay rich soils can occur. The conservation of cultural heritages in the studied areas will not be widely negatively affected, except for some single objects, by the studied parameters. / Kulturmiljöer är miljöer skapade av människan som anses ha ett bevarandevärde för eftervärlden. De kan ses som en av samhällets icke-förnyelsebara resurser. I och med de framtida klimatförändringarna är det viktigt att ha kunskap om hur bevarandet av kulturmiljöerna påverkas av dessa. I Uppsala kommer vattenflödena öka under vinterhalvåret men minska under våren och sommaren. Nederbörden kommer öka successivt och även perioder med intensiv korttidsnederbörd kommer öka. Även medeltemperaturen kommer öka. Trots den ökande nederbörden antas markfuktigheten minska, som resultat av den ökade medeltemperaturen med en ökad avdunstning som följd. Det här arbetet är utfört för Länsstyrelsen i Uppsala län, inom klimatanpassning på enheten för samhällsskydd och beredskap. Arbetet är inriktat på tre områden i Uppsala, stadskärnan, Hågadalen och Vallsgärde. Fokus i arbetet ligger på de geovetenskapliga konsekvenserna kopplade till översvämningar samt nederbördsförändringar. Kartor har producerats i ArcGIS där översvämningar, jordarter och kulturmiljöer redovisas (bilaga 1-3). 17 kulturmiljöer inom de tre områdena har konstaterats påverkas av översvämningar från Fyrisån varav merparten finns i Uppsala stadskärna. Förändringen av nederbörd är densamma över alla områden, till vilken grad det kommer att påverka kulturmiljöerna beror på kulturmiljöns karaktär. Marken bedöms inte påverkas nämnvärt av de ökade vattenmängderna. Mindre sättningar och skred i lerjordar kan dock uppkomma. Bevarandet av kulturmiljöer i de undersökta områdena kommer inte försvåras nämnvärt av undersökta parametrar, dock kan enskilda objekt påverkas mer.

From the Proceedings of the 1971 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 22-23, 1971, Tempe, Arizona / Previous studies have indicated that blue-green algae may affect runoff, infiltration and erosion at soil surfaces. Using soil plots upon which blue-green algae were grown under an artificial wetting regime, studies were made using simulated rainfall. A 30% clay content Pima soil and a contrasting 8% clay content river-bottom anthony soil were used. Scytonema hoffmanii and Microcoleus vaginatus grew on the pima soil while Schizothrix calcicola developed on the Anthony soil. The results showed that blue-green algal growths significantly reduced the amount of suspended soil material in runoff water as compared with bare soils. Differences in runoff suspended sediments were also related to differences in soil type and simulated rainfall intensity. An analysis of variance of the effects of these 3 factors and their interactions showed that the smaller differences in suspended sediment production on the Anthony soil due to the microvegetation treatment was verified by a highly significant soils-microvegetation interaction, probably because the finer pima soils wash away more easily without stabilizing microvegetation. Also, less vegetation seems to grow on the Anthony soil. Differences in runoff and infiltration volumes and in settleable sediment amounts were not detected.

From the Proceedings of the 1971 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 22-23, 1971, Tempe, Arizona / Snowmelt is a major source of runoff in Arizona for both reservoir systems and groundwater recharge. Because much of the Arizona snowmelt runoff occurs in ponderosa pine forests, it follows that appropriate forest management methods may enhance snowmelt water yield by manipulating tree spacing or overstory density. This paper attempts to establish guidelines for evaluating such forest management practices. Physiographic and climatic factors also affect runoff quantity, and it is conceivable that 2 sites of identical vegetation composition, but different in some combination of these factors might yield quite different amounts of runoff in response to some management practice. A pert network is presented illustrating the investigative framework for such a research effort. The major study activities of the framework are the identifying developing preliminary evaluations and preparing a comprehensive report. Three inventory evaluations to attempt identification of pertinent populations are currently being conducted and are described.

From the Proceedings of the 1974 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 19-20, 1974, Flagstaff, Arizona / Reported are laboratory evaluations to screen water-repellent materials and treatments before testing them in the field. Water repellency tests were conducted on paraffin wax, a wax emulsion and silicon, lard, and a liquid dust suppressant. Six water repellency tests showed that the high rates of paraffin wax and all rates of the dust suppressant produced highly water-repellent soil surfaces. The six water repellency tests were: (1) the aqueous-alcohol drop test for determination of the 90 degree surface tension for a porous solid, (2) the water drop penetration time test, (3) the relative height of a large sessile water drop resting on the smoothed, treated soil surface, (4) and (5) the presence and persistence of air bubbles trapped between the soil-water interface, and test (6) was made to note whether the large sessile water drop from test (3) would infiltrate the soil or evaporate. Tests (3), (4), and (5) proved the most useful of the six methods for measuring water repellency. Soil type had no significant influence on degree of water repellency as measured in the laboratory by these six tests.

From the Proceedings of the 1974 Meetings of the Arizona Section - American Water Resources Assn. and the Hydrology Section - Arizona Academy of Science - April 19-20, 1974, Flagstaff, Arizona / Population pressures on the land resources of Arizona have led to the sale and development of areas subject to flooding and because of the inadequacy of land use controls, the area is open to various land speculation schemes and unplanned subdivision growth. A floodplain delineation project was conducted for the planning department of Cochise County, Arizona, in which imagery acquired by earth resources technology satellite (ERT-1) and by high-altitude aircraft was employed. Parameters of the analysis included soils and geomorphology, vegetation, hydrologic calculations, and historical data. Floodplain soils lack developed b horizons, as compared to older, more mature soils not subject to flooding. General soil maps can only be used as guidelines, but a detailed soil survey can add significantly to the accuracy of image interpretations. Erosion-affected soil tones in areas adjacent to active channels proved beneficial in that the heightened contrast served to enhance resolution of vegetation-type boundaries. Hydrologic calculations were done based on valley cross-sections surveyed at two-to-three mile intervals. The historic data input into the system of floodplain delineation is dependent on the location of high-water marks and on obtaining a record of the amount of rainfall which resulted in the high-water mark.